The overarching goal of this research is to study how the brain controls gastric function. Specifically, these studies focus on GABAB receptors in the central components of the vago-vagal reflex. Current evidence implicates the GABAB receptor as a potential target for therapeutic interventions for gastric disorders such as gastroesophageal reflux (Holloway, 2001). In vivo microinjection techniques as well as immunohistochemistry will be used to determine how GABAB receptors in the brain stem influence gastric activity. The specific aims of this proposal are to: (1) determine the effects of microinjection of GABAB receptor agonists and antagonists into the DMV and NTS on intragastric pressure and gastric motility of the anesthetized rat; (2) determine the mechanisms underlying how GABAB receptor agonists and antagonists exert their effects on gastric motor activity upon microinjection into the DMV and NTS; and (3) determine whether the effects of intravenous administration of baclofen on gastric contractions are due either in part, or entirely to effects of the drug on GABAB receptors in the DMV and/or NTS.